从人员列表中提取名称列表
给定 Person
结构
struct Person {
let name: String
let birthYear: Int?
}
和一个 Person(s)
阵列
let persons = [
Person(name: "Walter White", birthYear: 1959),
Person(name: "Jesse Pinkman", birthYear: 1984),
Person(name: "Skyler White", birthYear: 1970),
Person(name: "Saul Goodman", birthYear: nil)
]
我们可以检索包含每个 Person 的 name
属性的 String
数组。
let names = persons.map { $0.name }
// ["Walter White", "Jesse Pinkman", "Skyler White", "Saul Goodman"]